Rear Pinion Torque

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
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Rear Pinion Torque

Post by jeepagain » Wed Sep 20, 2017 10:08 am

Wondering what the torque spec is for the nut that holds the yoke on the rear pinion. Can anyone help out?

Thx!
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Re: Rear Pinion Torque

Post by 1943Willysgpw » Wed Sep 20, 2017 1:22 pm

Check this out. Hopefully Jeepdraw does it again. http://jeepdraw.com/images/jeepdraw/TM1 ... R-AXEL.pdf
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Re: Rear Pinion Torque

Post by pittsjock » Wed Sep 20, 2017 3:12 pm

I have not found a torque spec in TM 9-1803B for either the front or rear differential pinion. The earlier series 10 TM's say to tighten "solidly". I see numbers for other differentials from 35 ft lbs to over 400.

I tightened mine to 60 ft lbs based on the size of the nut and then a little more to install the cotter key.

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Re: Rear Pinion Torque

Post by Ralph » Thu Sep 21, 2017 8:35 am

If the pinion has been set to the proper depth from carrier center-line,calculating that depth with pinion's rear face's offset value(if any mark is there)
and adjusted to that depth with shims...just tighten the nut solidly,toward a cotter hole while holding fast the yoke.Stop at the last hole you can.
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Re: Rear Pinion Torque

Post by ghiltgen » Fri Sep 22, 2017 10:36 pm

There's a guy on utube called metal shaper who has posted a lot of rebuild videos on vintage Willys jeeps. He has some on the rear axle for cj3a and if I remember correctly he was recommending 125 ft lbs for the yoke on the pinion. It's worth a watch and he lets people post questions which he answers fairly quickly, and will take emails. The WWII rear axle is probably similar but he could answer that if no one here can. We are already seeing a wide range of options from just tight enough to 60 ft lbs. So without clear documentation in TM it is a good question. A lot people redoing military jeeps are using them for parades and the like so they can get away with improper torques for awhile before anything bad happens.
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Re: Rear Pinion Torque

Post by Erikmaxlund » Sun Mar 01, 2020 5:38 am

After ben reading online seen everything from 30 to 200 lbs , the tm say solidly... Sooo Im only Get confused of reading online
Thought this was a very importen bolt/nut to Thighten right ????

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Re: Rear Pinion Torque

Post by Ralph » Sun Mar 01, 2020 6:50 am

Yes,an important nut to tighten.The TM suggests "solidly" because that is how it will feel, when tightened correctly.The yoke should be able to be turned by hand, but should not "coast" at release, with no perceptible fore & aft travel.There are no crush components in wartime gears, so if the yoke cannot be turned by hand after tightening, you may index it back 1 cotter-pin hole.Be sure of internals, shims,etc...
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Re: Rear Pinion Torque

Post by irakli » Sun Mar 01, 2020 7:05 am

After rebulding 4 axes I would say that torque nessesary to turn a
yoke depends on shims placed. The yoke nut shall be tightened to specs. My dino wrench's max is 210 nm. I put quite a force to reach that. It is lower than 200 (edited to ft.lbs) but I think it will be fine.
Last edited by irakli on Sun Mar 01, 2020 8:57 am, edited 1 time in total.
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Re: Rear Pinion Torque

Post by Wolfman » Sun Mar 01, 2020 7:44 am

I like 90 to 100 Ft. Lbs. on the nut, then tighten just enough more to get the cotter pin in place.
Turning force on the yoke once the nut is tight is something else and is measured in In. Lbs., not Ft.Lbs. This the rolling torque needed to rotate the assembled yoke and pinion ass. once the nut is tight. This would be more like 10 or 12 In. Lbs. when using new bearings. Adjusted by changing the shims behind the front pinion bearing.
200NM or Ft. Lbs. is too much on the big nut.
You just want to take up the slack in the pinion ass. and hold it securely together.
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Re: Rear Pinion Torque

Post by Rml1708 » Sun Mar 01, 2020 8:04 am

Please delete this reply
Last edited by Rml1708 on Sun Mar 01, 2020 8:21 am, edited 1 time in total.
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Re: Rear Pinion Torque

Post by Rml1708 » Sun Mar 01, 2020 8:08 am

Let me start off with I am no expert on this, but I just went thru all this on a dana25 with exploded spider gears.

There is so much more to the pinion than the torque on that yoke nut. The first measurement is pinion depth. Which is set by the shims under the bearing race/ cup on the pinion side. Then you work out the shims to set preload on the pinion. Google it up, the preload is 12 to 18 in-lbs depending on which chart you look at. This preload is set by adding or removing shims under the bearing on the yoke side of the pinion. I can not find any posted value for the torque on the nut. But if you go search up metalshaper on youtube I think he says 100 ft-lbs. Once you set the preload you get to set backlash. The backlash is supposed to be .006 to .010. This is adjusted by movement of shims on the carrier that moves the ring in or away from the pinion. Fun times, NOT.

If you truly are playing in the differentials, I highly recommend metalshapers you tube videos. Lots of subtle things going on in there that determine the life of the rear end. Did ya know that the carrier bearing caps were installed prior to line bore of the differential? They are marked uniquely so they go back in the right orientation. Just in case you wanted to know.

None of it's hard, it's just math and a lot of assemble, torque measure, remove and repeat until the numbers are right

Robert
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Re: Rear Pinion Torque

Post by JAB » Sun Mar 01, 2020 8:53 am

Rml1708 wrote:
Sun Mar 01, 2020 8:08 am
…………......……..
There is so much more to the pinion than the torque on that yoke nut. The first measurement is pinion depth. Which is set by the shims under the bearing race/ cup on the pinion side. Then you work out the shims to set preload on the pinion. Google it up, the preload is 12 to 18 in-lbs depending on which chart you look at. This preload is set by adding or removing shims under the bearing on the yoke side of the pinion. I can not find any posted value for the torque on the nut. But if you go search up metalshaper on youtube I think he says 100 ft-lbs. Once you set the preload you get to set backlash. The backlash is supposed to be .006 to .010. This is adjusted by movement of shims on the carrier that moves the ring in or away from the pinion. Fun times, NOT.

………...

None of it's hard, it's just math and a lot of assemble, torque measure, remove and repeat until the numbers are right

Robert
100% correct. Also, the model 23 (MB/GPW) and model 25 (CJ2,3,5,6 station wagon, truck front) Spicer axles are nearly identical in regard to the yoke and pinion. The spec for all models (23, 25, 41, 44) covered in the Service Manual For Willy-Overland Jeep Universal Vehicles Models CJ-2A CJ3A CJ3B CJ-5 CJ-6 DJ3A states to tighten the yoke to 200-220 lb-ft. This manual also mentions the model 23 (the early CJ-2A's used it) in the same chapter. The mid '50's Jeep Utility vehicle states, with a typo, 200 to 200 lb.-ft. As stated twice above, the tension on the yoke nut has no relationship to bearing preload (or turning torque/ease) as that is the function of the shims. The cotter pin is important, thus the range that should allow to get a hole to line up.
-Jeff

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Re: Rear Pinion Torque

Post by irakli » Sun Mar 01, 2020 9:28 am

I am following the specifications provided in this chart, they are compilation from 45, 53 and 65 manuals. I guess in 1945 Dana 23/25 was still used on CJ-2a:

http://www.cj-2a.com/techtips/specs/torques.html

I my country we are using metric system, so inch pounds, foot pounds, inch ounces was quite confusing for me (I still made mistake in above post). I managed to get correct tool only at the third attempt :oops: :
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Re: Rear Pinion Torque

Post by JAB » Sun Mar 01, 2020 9:51 am

-Jeff

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Re: Rear Pinion Torque

Post by donk_316 » Sun Mar 01, 2020 11:49 pm

Hold on... I thought it was a drag torque rating other than a bolt torque rating? Like you bolt up the pinion and then tighten until you needed 30 foot pounds of force.


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